You may not bring a mutant vehicle to Burning Man unless the questionnaire has been filled out and then subsequently approved/invited to bring to the playa (where it will still need to pass on-playa inspection). If you just make and bring something anyways, you risk it getting impounded in D-lot for the entire week, as well as potentially making it more difficult to get approved in subsequent years. If you get inspired to build some completely different thing in July, awesome - start working on it for next year's burn.
All this info should also be available on the 'Vehicles At Burning Man
' section of the site, which you should read through before considering building/bringing vehicles to the event.